hello, i have 91 z28 tpi but having trouble with the vats system done alot of things just tired of it would like to know if i could use a harness that doesn't have vats like from an 88 iroc tpi will this work? and woud the harness fit exactly in the firewall next the brake booster? any help would be greatly appriciated

 

have to move a few wires around. actually not that hard as i just did it last week. just working out the bugs. wouldn't really be worth it for you tho seeing as you already have tpi.

 

so the 88 harness connecter will fit directly in to the 91 body connecter ? thanks for the help

 

No!

Just have the VATS removed from the prom.

 

Changing the harness won't help you because the computer would still be looking for the VATS signal. Easiest way to go would be have a chip programmed for the car with VATS disabled.

 

Do a search, there are a few ways to disable the vats.using the correct resistor is the easiest and cheapest.did mine 5 years ago ,no problems. Good luck

 

Works great if the only problem is the wiring to the lock cylinder. If the passkey module is at fault, or any other interconnecting wiring, this fix won't work.

 

dont get it how can the computer look for a vats signal if the computer from an 88 doesnt have vats remember i want to put a harness from an 88 . 91 and 88 use diffrent computer's

 

Because you NEVER MENTIONED swapping over the computer as well
Only swapping in a 88 harness
Your words
"would like to know if i could use a harness that doesn't have vats like from an 88"

If you install a 88 computer on the 88 harness and swap from MAP to '88 MAF setup then your problem is solved
Or spend $100 to get VATS disabled on prom and change nothing

 

Swapping the entire engine control system from '91 speed-density to '88 MAF-based is going to cost you more than the chip would, not to mention being FAR more time and trouble to do. Doesn't the '88 system require the use of a cold-start injector? Oops. Now you have to switch intake manifolds too.

Seriously. Just have a chip burned for it to disable VATS, and the speed limiter if you're feeling froggy. It's the best way to go.

 

well i thought is was obvious because 91

 

well i thought it was obvious because a 91 harness wont fit an 88 computecr because they use diffrent computer's so i would be forced to use one from an 88 . so do you all think that the connecter that connects to the body is the same for 91 and 88

 

What he said......

 

didnt read the first part about vats.... too early for me. have to agree with these guys, just bypass vats or have it programmed out. i thought you asked about changing to maf from map. i did change my tbi to maf but i retained my vats system as i just replaced the whole system. there is alot of information, just search and read everything.......

 

There are newbies like you on here that don't even know they have a computer ;
let alone that there are different types.
Best to define clearly what you want to do so people don't " assume"

Compare what wiring has to run back from engine to ECM; looks like so changes would be needed
see
http://www.austinthirdgen.org/index.php?pid=19

 

ok so where would i send my prom to get the vats removed and would i have to do anything else? thanks for the help sorry for any confusion its just that wanted to do this as soon as possible friend has harness and everything i need willing to try without paying to see if it works sort of an expiremnt. and about the cod start i have an 88 iroc that i dont have this connected and it works mjust fine?

 

You don't
They send you a piggyback chip to install
http://www.pcmforless.com/index.php?...128&Itemid=341

Or you buy a $25 module that wires to your computer to give the require VATS fuel enable signal it is looking for

http://www.bakerelectronix.com/products_vats/

 

I dunno about "forced." There are quite a few guys on this site using a MAP-based system in cars that were originally MAF equipped using the original wiring harness. I'm one of them. All it takes is moving some pins around in the ECM connector...not that hard to do at all, and going the other way would be just as easy. In fact it'd be much easier to repin your current harness to '88 specs than to pull out and replace the harness altogether. I still wouldn't fool with it though.

 

thanks alot guys ima order that piggy back and that doesnt work im removing the harness .. and ill see what happens thanks for everything

 

the part of the harness that plugs into the firewall will need to be repinned. 88 and 91 were different

like others have said it would be easier just to get a custom chip made.